1. Field of the Invention
The present invention relates to an information processing unit, an output of which can be viewed by using a home use television or a television monitor, and the information processing unit can optimally display an image. Particularly the present invention relates to a technology for adjusting a television video signal before the signal is displayed on a television screen.
2. Description of the Related Art
A television set for home use or a television monitor (not having a VHF function) is provided with an S video terminal (for separate luminance and chrominance signals) or a terminal for inputting a composite signal. External video sources are connected to the above terminals, the composite signal or YC separated signals (Y signal: luminance signal, C signal: chrominance signal) are input, and an image is displayed on a television set for home use or the like.
Some home use television sets are provided with an image correction circuit by which specific frequency components (e.g., from 2 MHz to 3 MHz) of the video signal are amplified and an adjustment of the image is executed.
Image sources for home use television sets are not always the output of a video tape recorder or a television broadcast signal, but recently may also include an image from a computer (or information processing unit). Namely, sometimes the output of a computer is not applied only to an exclusive display. The computer image may be displayed on a television monitor having an input terminal for a composite video signal or a YC separated signal as an external input. By displaying the computer output on the home use television set, if the user provides only the main unit of a personal computer (i.e., if the display for the computer is not provided), the personal computer can still be utilized. In this case, the home use television set or the television monitor is connected to the computer to receive a composite video signal or an S video terminal signal, and the image from the computer can be displayed without using an exclusive display for the personal computer.
To display the image from a personal computer on a home use television set, the personal computer must output either an S video signal or a composite video signal that can be used in the home use television.
However, when a television monitor with an image correction circuit as mentioned above is used and the computer image is output thereon, specific frequency components are corrected in the television monitor, and the image may tend to glare. For example, if the television monitor emphasizes the edges of images, the image output from the computer is also emphasized in the edges, thereby causing an glaring effect. This emphasis of the edges is sometimes not necessary when the image from a personal computer is displayed.
Accordingly, if the correction is not carried out by the television monitor, the image from the computer can be displayed without glaring. However, if the television monitor is provided with a fixed correction, i.e., the user cannot alter the correction, the correction cannot be prevented. Recently, with some television monitors or the like the amount of image correction can be set by the user, however, this is troublesome if the user must turn off the image correction whenever the image to be displayed is output from a computer.